A brief excerpt from Leonard Peikoff's Objectivism: The Philosophy of Ayn
Rand

There is no question more crucial to man than the question: what is man? What
kind of being is he? What are his essential attributes?

Many thinkers and artists have sought to answer this question. They have looked
at men and then offered a report on man's nature. Their reports have clashed
through the ages. Aristotle defined man as the "rational animal."
Plato and the medievals described other-worldly souls trapped in a bodily
prison. Shakespeare dramatized man as an aspiring but foolish mortal, defeated
by a "tragic flaw." Thomas Hobbes described a mechanistic brute. Kant
saw man as a blind chunk of unreality, in hock to the unknowable. Hegel saw a
half-real fragment of the state. Victor Hugo saw a passionate individualist
undercut by an inimical universe. Friedrich Nietzsche saw a demoniacal
individualist run by the will to power. John Dewey saw a piece of flux run by
the expediency of the moment. Sigmund Freud spoke of an excrement-molding
pervert itching to rape his mother.